Add SQLHelper and CenterAlignSqlTableModel. The CenterAlignSqlTableModel only make the cell text align center.

src/db/CenterAlignSqlTableModel.cpp

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+//
+// Created by Krad on 2021/10/11.
+//
+
+#include "CenterAlignSqlTableModel.h"

src/db/CenterAlignSqlTableModel.h

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+//
+// Created by Krad on 2021/10/11.
+//
+
+#ifndef GUI_CENTERALIGNSQLTABLEMODEL_H
+#define GUI_CENTERALIGNSQLTABLEMODEL_H
+
+#include <QSqlTableModel>
+class CenterAlignSqlTableModel:public QSqlTableModel {
+    Q_OBJECT
+public:
+    explicit CenterAlignSqlTableModel(QObject *parent = nullptr, QSqlDatabase db = QSqlDatabase()):QSqlTableModel(parent,db){};
+    ~CenterAlignSqlTableModel(){};
+protected:
+    QVariant data(const QModelIndex& index, int role) const override {
+        if (index.column() >0 && role == Qt::TextAlignmentRole) {
+            return Qt::AlignCenter;
+        } else {
+            return QSqlTableModel::data(index,role);
+        }
+    }
+};
+
+
+#endif //GUI_CENTERALIGNSQLTABLEMODEL_H

src/db/SQLHelper.cpp

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+//
+// Created by Krad on 2021/10/11.
+//
+
+#include "SQLHelper.h"
+
+#include <QSqlDatabase>
+#include <QSqlQuery>
+QSqlDatabase* SQLHelper::defaultDatabase= nullptr;
+QHash<QString,CenterAlignSqlTableModel*>* SQLHelper::cache= new QHash<QString,CenterAlignSqlTableModel*>;
+bool SQLHelper::Open() {
+    if (defaultDatabase) return true;
+    defaultDatabase=  new QSqlDatabase(QSqlDatabase::addDatabase("QSQLITE", "USCTDB"));
+    defaultDatabase->setDatabaseName("USCTDB.data");
+    return defaultDatabase->open();
+}
+
+bool SQLHelper::Open(QSqlDatabase *base) {
+    if(base && base != defaultDatabase){
+        defaultDatabase = base;
+    }
+    return defaultDatabase->open();
+}
+
+void SQLHelper::Close() {
+    for(auto item : cache->values())
+    {
+        delete item;
+    }
+    cache->clear();
+    if(defaultDatabase->isValid() && defaultDatabase->isOpen())
+    {
+        defaultDatabase->close();
+        delete defaultDatabase;
+        defaultDatabase = nullptr;
+    }
+}
+
+QSqlTableModel* SQLHelper::getTable(const QString &tableName) {
+    if (cache->contains(tableName)) return (*cache)[tableName];
+    CenterAlignSqlTableModel *model = new CenterAlignSqlTableModel(nullptr,*defaultDatabase);
+    model->setTable(tableName);
+    (*cache)[tableName] = model;
+    return (*cache)[tableName];
+}

src/db/SQLHelper.h

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+//
+// Created by Krad on 2021/10/11.
+//
+
+#ifndef GUI_SQLHELPER_H
+#define GUI_SQLHELPER_H
+
+class QSqlDatabase;
+#include "CenterAlignSqlTableModel.h"
+#include <QString>
+#include <QHash>
+
+class SQLHelper {
+public:
+    static bool Open();
+    static bool Open(QSqlDatabase* base);
+    static void Close();
+    static QSqlTableModel* getTable(const QString & tableName);
+private:
+    static QSqlDatabase*  defaultDatabase;
+    static QHash<QString,CenterAlignSqlTableModel*>* cache;
+};
+
+
+#endif //GUI_SQLHELPER_H